The present invention relates generally to vehicle wheels and particularly to an improved combination steel and aluminum vehicle wheel.
A typical automobile wheel comprises an annular, tire-supporting rim that is welded to a central spider. The spider mounts to an axle of the automobile. Both the rim and the spider are typically made from steel with the rim being roll formed and the spider being stamped.
In use, a vehicle wheel is continuously subjected to forces tending to deform the rim from its initial circular shape. Circumferential deformation of the rim is induced by the vertical component of vehicle load as well as by severe road conditions, e.g., bumps, potholes, etc. Since the wheel spider experiences a relatively small amount of deformation, a bending moment is induced at the welded juncture of the spider and rim. Thus, such known wheels must rely solely on the strength of the steel spider, rim, and the weld therebetween.
Recent emphasis on high performance vehicles has created a need for a wheel configuration that is extremely strong yet effects cooling of the vehicle braking system. Cast aluminum wheels exhibit relatively efficient heat transfer characteristics and, in addition, are often provided with integral fins that function as fan blades to induce a flow of cooling air over the brake drum or disc. However, such wheels are inherently weaker than steel wheels and the cost of such wheels is a high multiple of the cost of a steel wheel. While fan characteristics can be molded into current plastic wheel covers, such covers do nothing to augment wheel strength.